Botany Exam 3

Plant Toxins and the Heart | What Chili Peppers Can Teach Us about Pain | Weekly Quiz 8 | Muscles & Plant toxins | Weekly Quiz 9 | A Boosted Crop | Review Exam 3 |

Why did plants evolve toxins?

To protect from being eaten by herbivores

Family of Aconite Alkaloid

Ranunculaceae family

Family of Taxus Alkaloids

Taxaceae family

Cardiac Glycosides

Sugars that contain steroids, can be produces by some plants and toads

Sodium-Potassium Pump

A protein pump that pumps Sodium and potassium against the gradient. This uses ATP-Hydrolysis.

Action Potential

Change in voltage in the cell membrane, often in neurons

What is the difference between simple diffusion and active transport?

Simple diffusion goes along a gradient, while active hydrolyses ATP

Functions of Sodium-Potassium Pump, what gets pumped in what direction?

1. Pump sodium Ions outside the cell

2. Pump potassium inside the cell

Format of Action Potential, what is the order of operation?

Stimuli past threshold → depolarization → Action potential → repolarization → Hyperpolarization → resting state

Electrical Conduction System of the four chambered heart

Nerves controlling the Heart

Sympathetic Nerves and Parasympathetic nerves

Functions of Sympathetic Nerves

• releases norepinephrine

• increases heart rate

• controls contraction

• receptor of norepinephrine is beta-1-adrenergic receptor

Functions of Parasympathetic Nerves

• releases acetycholine on heart tisue

• deceases heart rate

• Receptor for acetylcholine on heart cells is muscarinic type and binding of Acetylcholine to its receptor, leading to opening of K+ channels causing hyperpolarization, therefore the effect on heart rate.

What happens during Fight or Flight?

The pituitary and adrenal glands release catecholamines, including adrenaline, noradrenaline, and cortisol. This chain of reactions results in an increased heart rate, blood pressure, and breathing rate

Why do tropane Alkaloids from deadly nightshades increase heart rate?

Atropine and other tropane alkaloids prevent binding of the neurotransmitter acetylcholine to its receptor and, as a result, they cause blurred vision, suppressed salivation, vasodilation, increased heart rate, and delirium

Different Aconite Alkaloids

1. Aconitine - Most toxic

2. Atisine - Nerves

3. Veatchinine - Milder

Symptoms of Aconitine

Arrhythmias, and effects on the heart

Symptoms of Atisine

numbness and tingling, affects the nerves

Structure of Aconitum

Species of Aconitum and their causes

• 350 species around the world

• poison (arrow)

• common causes

  • contamination

  • adulteration

Mechanisms of Aconitines

Agonist of voltage gated Na Channels, keeping them open longer and delaying repolarizations. This can cause weakness, numbness, vomiting, dizziness, arrhythmia, coma, and death.

Knowing the harms of Aconitines, what warning would you give to florists?

Wear gloves, wash hands, don’t use fatty lotions.

Family of Aconite

Rosaceae - Rose Family

Example species of Aconite

Spirea japonica (toxin from veatchine group - least toxic)

Example species of Aconitum

Monkshood

Example species of Taxus

Yew, common ornamental shrub/tree, a non flowering conifer

Common trait of Taxus Baccata L.

The seeds are toxic, not the fleshy covering

Aril

accessory covering certain seeds, found in both gymnosperms and angiosperms.

What is the difference between Juniper and Yew?

A juniper Berry is the female seed cone, but it is not a true berry. It is a cone with fleshy scales.

Order - Pinales

Family - Cupressaceae: Juniperus L.

Taxaceae: Taxus L.

What does the “L” stand for in some names

The first letter of the last name of who discovered it, for example “Linnaeus”

History of Yew Trees

• Slow growing

• Oldest in Europe, Wales church yard, around 5,000 years old

• All parts are toxic after drying except aril

• some deer can browse it

Taxine B

From Taxaceae family

In plant leaves and seeds

edible red aril

antagonist of calcium sodium channels

causes: Hypotension, cardiac arrest, and death

Taxol

Paclitaxel

Binds tublin, which prevents breakdown, induces apoptosis, often used with other drugs to fight cancer.

Docetaxel

demi-synthetic analogue

Cardiac Glycosides Flavors

Cardenolide and Bufadienolides

Cardenolide Structure

Bufadienolides Structure

Cardiac Glycosides Families

• Apocynaceae

• Plantaginaceae

• Asparagaceae

• Ranunculaceae

Glycosides Structures

Sugars with Hydroxyl groups + Glycosidic Bonds + Aglycone

Cardiac Glycosides effect on Sodium-Potassium pump

Pump is blocked by cardiac glycosides

• cellular Na increase

• Intracellular Ca causes muscle contraction (troponin

  • irregular, intense, can cause death

• Treated with atropine

  • stimulates heart

Apocynaceae (Dogbane Family)

• 5000 spp

• Most toxic to some degree

• can produce cardioactive steroids and monoterpene indole alkaloids

  • Effects the nervous system

The Monarch Butterfly and Milkweed plant

Caterpillars the feast on the Asclepias spp, and stores the toxin as an a adult.

Digitalis lanata family and toxin

• From Plantaginaceae family

• creates digoxin

Strophanthus kombe family and toxin

• From Apocynaceae family

• creates g-Strophanthin (ouabain)

• Arrow poison kills elephants

Case of Digoxin, use in medicinal practice

Used to treat patients with heart failure due to calcium forcing contractions.

Strophanthus spp. (Toxin and its effects)

• ouabain

  • increase cardiac output (not heart rate)

    • increase contraction strength

  • less absorbed by GI tract, rapidly eliminating

Digoxin (Medicinal use)

• used in systolic heart failure (weak left ventricle)

  • increase contraction strength

• reduces hospitalizations

Nerium oleander, family and toxin

• From Apocynaceae family

• Contains Oleandrin

  • Entire plant is toxic, dry and wet

Ranunculaceae, toxin present and example species.

Similar cardenolide type cardiac glycosides present in some general of buttercup

Adonis (Pheasant’s eye)

Asparagaceae Family, example and toxin

Example: Convallaria majalis (lily of the valley)

Creates convallotoxin, a cardiac glycoside

Functions of Aril

The fleshy red coverings found in yew trees, it lacks cardiotoxic alkaloid, taxine B, which targets Sodium calcium Channels.

convallotoxin - structure

Khat

Catha edulis (Celastraceae)

Chewed where alcohols is banned, acts as a stimulate

Common education about plants

• do not eat random plants

• don’t drink random nectar

• learn about plants you bring home

• keep plants away from kids and pets

• don’t burn random plants

• don’t cook with random plants

• don’t use fatty hand lotions

Alcohol from Juniperus

Gin, only alcohol from Cucurbitaceae

How would you introduce Dr. D Julius to a cell and molecular/biomedical sciences class?

Dr. David Julius, known for his work on pain sensation, identified the TRPV1 receptor activated by capsaicin, significantly advancing our understanding of pain perception. His research also extends to studying diverse sensory systems, such as infrared sensing in snakes and electroreception in aquatic animals.

What is the main theme of work of Dr. David Julius?

The main theme of Dr. David Julius's work is the understanding of pain sensation and the molecular mechanisms underlying sensory perception.

Which stimuli that can impact/trigger the TRPV1 receptor in the peripheral nervous system?

• Heat

• Capsaicin (found in chili peppers)

• Inflammatory chemicals, contributing to heightened sensitivity during injury.

What it a TRP receptor?

TRP receptors are cellular ion channels involved in sensory processes, including temperature and taste perception, contributing to physiological regulation and sensation.

What are the different types of TRP receptors and what are their stimuli?

1. TRPV (Vanilloid) receptors:

   • Stimuli: Heat, capsaicin, protons, endovanilloids

2. TRPM (Melastatin) receptors:

   • Stimuli: Temperature, voltage, osmolarity, taste molecules

3. TRPC (Canonical) receptors:

   • Stimuli: Phospholipase C-dependent pathways, including G-protein-coupled receptors

4. TRPA (Ankyrin) receptors:

   • Stimuli: Cold temperatures, environmental irritants, reactive oxygen and nitrogen species

Where in humans are the different types of TRP receptors found?

1. TRPV (Vanilloid) receptors:

   • Found in sensory nerve endings, the skin, and the bladder

2. TRPM (Melastatin) receptors:

   • Located in the brain, the kidneys, and the heart

3. TRPC (Canonical) receptors:

   • Found in smooth muscle cells, the brain, and the kidneys

4. TRPA (Ankyrin) receptors:

   • Present in sensory neurons, the respiratory system, and the gastrointestinal tract

How do different TRP receptors function?

1. TRPV (Vanilloid) receptors:

   • Respond to temperature changes, as well as specific chemical stimuli, such as capsaicin and protons.

2. TRPM (Melastatin) receptors:

   • Regulate calcium and magnesium ion flow, responding to temperature, osmolarity changes, and various taste molecules.

3. TRPC (Canonical) receptors:

   • Operate as non-selective cation channels, mediating calcium influx and contributing to various intracellular signaling pathways.

4. TRPA (Ankyrin) receptors:

   • Participate in detecting environmental irritants, cold temperatures, and reactive oxygen and nitrogen species, leading to the sensation of pain and inflammation.

What is the Wasabi receptor?

The "Wasabi receptor" refers to the TRPA1 receptor, which is activated by compounds found in wasabi, as well as by environmental irritants, cold temperatures, and reactive oxygen and nitrogen species.

What plant family has roots that impacts the wasabi receptor (TRPA1)?

Brassicaceae family, such as wasabi, horseradish, and mustard

How did the wasabi receptor (TRPA1) gain notoriety?

gained attention due to its involvement in sensing environmental irritants, cold temperatures, and reactive substances, contributing to the sensation of pain and inflammation

What roles do the TRP receptors play in human behavior?

TRP receptors play essential roles in mediating sensations such as temperature, taste, and pain perception, thereby influencing human behavior through the interpretation of external environmental stimuli and the regulation of physiological responses

What groups of people may have issues with the functions of TRP receptors?

Individuals with conditions such as diabetes or leprosy, which can lead to reduced sensation in extremities

Where are opioid receptors?

• Brain

• Spinal cord

• Peripheral sensory neurons

What are 3 effects opioid receptors can have on humans?

• Pain relief

• Euphoria or feelings of well-being

• Respiratory depression

Characterize what is meant by “on-target side effects”

"On-target side effects" refer to unintended physiological effects that occur due to the specific interaction of a drug with its intended target

What exciting sensory field is considered a frontier of new research?

Infrared sensing, particularly in snakes, is an exciting sensory field considered a frontier of new research endeavors

Why could infrared sensing contribute to our understanding of pain?

Studying infrared sensing could enhance our comprehension of pain as it shares neural pathways with other sensory processes

What long range outcome does research on infrared sensing and pain receptors hope to address?

Research on infrared sensing and pain receptors aims to advance pain management strategies and develop innovative non-opioid pain treatments

Wasabi was mentioned in the reading. What is the plant family previously discussed in class?

Brassicaceae

What are the TRPV1 receptors mainly located?

Peripheral Nervous System

What inspired Dr. Julius’ interest in pain?

• Supermarket Visit

• Use of Peyote

• curiosity of the function of neurotransmitters

• folk medicine and use of natural products

Hansen’s disease patients and some individuals with complications from diabetes lack the ability to perceive pain.

True

Capsaicin is a/an _____ that binds to the TRPV1 receptor

agonist

You feel the hot chili pepper on your lips when the primary afferent sensory neuron and nociceptors send a signals to a second neuron in the spinal cord eventualy gets taken to the brain centers where you sense something noxious and painful. This particular receptor also binds to ___ and ___ agents.

Heat, inflammatory

Digoxin has been used as a drug for systolic failure because it

increases cardiac output

Taxaceae (visual examples)

In the “Unearthed” podcast Lakhvinder Cheema was murdered on 27 January 2009 in Southall, west london, by his former lover, Lakhvir Kaur Singh through the use of poison derived from the ____ plant, which contain the highly toxic alkaloid ____.

Aconitum , Pseudaconitine

Strophanthus kombe produces the toxin ouabain, its extract known as kombe has famously been used as an arrow poison to kill which of the following animal?

elephant

Which of the following are used in traditional chinese medicine?

• Spirea japonica

• Angelica sinensis

You made a fire and threw in the plants that sprouted on the path near your country house. As soon as the fire flared up, you recognized one of the plants as Nerium oleander. Should you be concerned and what could you do?

Yes, and you should immediately extinguish the fire only if safely possible or immediately seek help to do so

What medication is used to eliminate the toxin effects of cardiac glycosides?

atropine, a propane alkaloid

Which of the following plant families produces the secondary metabolite digoxin, a compound that is used to treat systolic heart failure.

Plantaginaceae

Docetaxel is a semi-synthetic version of the toxin paclitaxel and is used as a cancer treatment. Which of the following is it's correct mechanism of action?

Binds to surface receptors and triggers apoptosis

Three types of muscles

• Skeletal

  • voluntary control

• Smooth muscle

  • autonomic nervous system

    • GI tract

    • blood vessels

    • airways

    • eye

    • uterus

    • bladder

• Cardiac

  • Heart, autonomous activity but also influenced by nervous system

Autonomic Nervous System, divisions and their functions

• Parasympathetic division

  • rest and digest

  • muscarinic

  • releases acetylcholine

• Sympathetic division

  • flight and fight

  • nicotinic

Two types of ACh (Acetylchloine) receptors

• Nicotinic

• Muscarinic

ACh (Acetylcholine) Structure

Neuromuscular junction, order of operations

1. Action potential depolarizes the nerve terminal

2. Voltage gated Ca2+ channels allow Ca+2 influx

3. Ca2+ evoked vesicle exocytosis of ACh

4. ACh activates AChRs

5. Cation influx through AChRs depolarizes muscle fibers forming EPP

6. Voltage gated Na+ channels generate action potential

7. AChE degrades ACh to terminate the signal

Neuromuscular junctions | diagram

What nerve and chemical targets smooth muscles?

Nervous systems and hormones

Paralyzing Curares are from which families

• Menispermacea

• Logoniaceae

• Fabacea

Piperidine Alkadloids families

• Solanaceae

• Apiaceae

Quinolizidine family

• Fabaceae

Example of Menispermaceae

Chondrodendron tomentosum